Mariner Mars 1971 spacecraft destruct unit

Shaped charge destruct unit for Mariner Mars 1971 spacecraf

High-repetition-rate femtosecond laser processing of acrylic intra-ocular lenses

The study of laser processing of acrylic intra-ocular lenses (IOL) by using femtosecond laser pulses delivered at high-repetition rate is presented in this work. An ultra-compact air-cooled femtosecond diode laser (HighQ2-SHG, Spectra-Physics) delivering 250 fs laser pulses at the fixed wavelength of 520 nm with a repetition rate of 63 MHz was used to process the samples. Laser inscription of linear periodic patterns on the surface and inside the acrylic substrates was studied as a function of the processing parameters as well as the optical absorption characteristics of the sample. Scanning Electron Microscopy (SEM) Energy Dispersive X-ray Spectroscopy (EDX), and micro-Raman Spectroscopy were used to evaluate the compositional and microstructural changes induced by the laser radiation in the processed areas. Diractive characterization was used to assess 1st-order efficiency and the refractive index change

Feed preference in pigs: Relationship between cereal preference and nutrient composition and digestibility

The present work aimed to identify the nutritional characteristics that best explain cereal feed preference in pigs. A total of 25 cereals of known preference (at 60% of inclusion in complete feed) from a previous study were evaluated. The cereals were analyzed for DM, OM, crude fiber, ether extract, CP, GE, digestible starch, and glycemic index. Additionally, for 12 of the cereals, complete feeds (the same composition as those previously used to measure preference) were prepared, analyzed for DM, OM, CP, and starch, and fed to pigs (33 ± 5.1 kg BW) fitted with ileal T-cannulae to assess the apparent ileal (AID) and total tract digestibility (ATTD) of these nutrients using titanium dioxide as an indigestible marker. The relationships among the different energy and nutrient contents were studied by principal component (PC) analysis, and the correlations between the generated PC scores and cereal preference were analyzed. A correlation between preference and the second PC obtained with data of the 25 cereals was observed (P < 0.01), which indicated that crude fiber (negatively) and digestible starch, OM, and glycemic index (positively) were correlated with feed preference. Statistically significant linear relationships with preference were confirmed for crude fiber, digestible starch, and glycemic index (R = 0.38, 0.36, and 0.23, respectively; P < 0.02). Similarly, the first PC obtained with data of the 12 feeds also correlated with preference (P < 0.01), indicating that the digestible nutrients (positively) and the nondigestible nutrients (negatively) were correlated with preference. Statistically significant relationships with preference were observed for the contents of starch (total, digestible AID, and digestible ATTD: R = 0.62, 0.66, and 0.63, respectively; P < 0.01), AID DM (digestible and nondigestible: R = 0.41 and 0.44, respectively; P < 0.05), ATTD DM (digestible and nondigestible: R = 0.67 and 0.70, respectively; P < 0.01), AID OM (digestible and nondigestible: R = 0.45 and 0.43, respectively; P < 0.05), and ATTD OM (digestible and nondigestible: R = 0.64 and 0.66, respectively;

Maximum likelihood estimation in possibly misspecified dynamic models with time-inhomogeneous Markov Regimes

This paper considers maximum likelihood (ML) estimation in a large class of models with hidden Markov regimes. We investigate consistency and local asymptotic normality of the ML estimator under general conditions which allow for autoregressive dynamics in the observable process, time-inhomogeneous Markov regime sequences, and possible model misspecification. A Monte Carlo study examines the finite-sample properties of the ML estimator. An empirical application is also discussed

Longitudinal spin Seebeck coefficient: heat flux vs. temperature difference method

The determination of the longitudinal spin Seebeck effect (LSSE) coefficient is currently plagued by a large uncertainty due to the poor reproducibility of the experimental conditions used in its measurement. In this work we present a detailed analysis of two different methods used for the determination of the LSSE coefficient. We have performed LSSE experiments in different laboratories, by using different setups and employing both the temperature difference method and the heat flux method. We found that the lack of reproducibility can be mainly attributed to the thermal contact resistance between the sample and the thermal baths which generate the temperature gradient. Due to the variation of the thermal resistance, we found that the scaling of the LSSE voltage to the heat flux through the sample rather than to the temperature difference across the sample greatly reduces the uncertainty. The characteristics of a single YIG/Pt LSSE device obtained with two different setups was $(1.143\pm0.007)\cdot 10^{-7}$ Vm/W and $(1.101\pm0.015)\cdot 10^{-7}$ Vm/W with the heat flux method and $(2.313\pm0.017)\cdot 10^{-7}$ V/K and $(4.956\pm0.005)\cdot 10^{-7}$ V/K with the temperature difference method. This shows that systematic errors can be considerably reduced with the heat flux method.Comment: PDFLaTeX, 10 pages, 6 figure

Directionally solidified fabrication in planar geometry of Al2O3-Er3Al5O12 eutectic composite for thermophotovoltaic devices

In this work Al2O3-Er3Al5O12 eutectic composite was manufactured in planar geometry departing from eutectic particles both produced by directional solidification using a CO2 laser system at rates of 180 and 720 mm/h. Microstructure and mechanical properties were investigated as a function of the growth rate. Homogeneous and interpenetrated microstructure was found with phase size strongly dependent on the growth rate, decreasing when the processing rate was increased. Thermal emission of eutectic composites was studied in function of thermal excitation by using CO2 laser radiation as a heating source. An intense narrow emission band at 1.55 µm matching with the sensitive region of the InGaAs photoconverter and a low emission band at 1 µm were obtained. Features of thermal emission bands were correlated with collecting angle, microstructure and laser power, and compared to those obtained from departing eutectic particles

Diabetes as an outcome predictor after heart transplantation

We aimed to compare post-transplantation morbidity and survival among heart transplant recipients with and without diabetes mellitus. A retrospective review of 141 adult patients submitted to heart transplantation from November 2003 to June 2009 (with a minimum follow-up of one year) was undertaken. The patients were divided into two groups: those with (29%) and those without (71%) pre-transplantation diabetes. Those with diabetes were older (57.6±6.1 vs. 52.3±11.1 years; P=0.020) and had lower creatinine clearance (53.6±15.1 vs. 63.7±22.1; P=0.029). Nine patients died in hospital (6.4%; P=non-significant). No significant differences in lipid profiles (diabetes vs. no diabetes) existed before transplantation or at one year afterwards. Patients with diabetes showed a significant deterioration in their one-year lipid profile (158±43 vs.192±38 mg/dL; P=0.001), although one-year fasting diabetic was lower than before (178±80 vs. 138±45 mg/dL; P=0.016). During the first year, 17 (17%) patients previously free of diabetes developed new-onset diabetes. No significant differences were seen in rejection at one year (14% vs. 20%), infection (31% vs. 33%), new-onset renal dysfunction (8% vs. 14%) or mortality (17% vs. 7%). One-year survival was not significantly different (83% vs. 94%), but there was a significant decrease in the survival of individuals with diabetes at three years (73% vs. 91%; P=0.020). No significant difference was found in one-year survival or in terms of higher morbidity in the heart transplant patients with diabetes, but a longer follow-up showed a significant decrease in survival. Nonetheless, the patients with diabetes benefited significantly from transplantation and should not be excluded from it

Site-selective laser spectroscopy of Nd 3+ ions in 0.8CaSiO 3-0.2Ca 3(PO 4) 2 biocompatible eutectic glass-ceramics

In this work we report the influence of the crystallization stage of the host matrix on the spectroscopic properties of Nd3+ ions in biocompatible glass-ceramic eutectic rods of composition 0.8CaSiO3-0.2Ca3(PO4)2 doped with 1 and 2 wt% of Nd2O3. The samples were obtained by the laser floating zone technique at different growth rates between 50 and 500 mm/h. The microstructural analysis shows that a growth rate increase or a rod diameter decrease leads the system to a structural arrangement from three (two crystalline and one amorphous) to two phases (one crystalline and one amorphous). Electron backscattering diffraction analysis shows the presence of Ca2SiO4 and apatite-like crystalline phases. Site-selective laser spectroscopy in the 4I9/2¿4F3/2/4F5/2 transitions confirms that Nd3+ ions are incorporated in crystalline and amorphous phases in these glass-ceramic samples. In particular, the presence of Ca2SiO4 crystalline phase in the samples grown at low rates, which has an excellent in vitro bioactivity, can be unambiguously identified from the excitation spectra and lifetime measurements of the 4F3/2 state of Nd3+ ions

Control of bulk superconductivity in a BCS superconductor by surface charge doping via electrochemical gating

The electrochemical gating technique is a powerful tool to tune the surface conduction properties of various materials by means of pure charge doping, but its efficiency is thought to be hampered in materials with a good electronic screening. We show that, if applied to a metallic superconductor (NbN thin films), this approach allows observing reversible enhancements or suppressions of the bulk superconducting transition temperature, which vary with the thickness of the films. These results are interpreted in terms of proximity effect, and indicate that the effective screening length depends on the induced charge density, becoming much larger than that predicted by standard screening theory at very high electric fields