Excavaciones en el sepulcro megalítico de Ca Na Costa (Formentera)

Abstract not availabl

Tribological enhancement of potential electric vehicle lubricants using coated TiO2 nanoparticles as additives

This work presents the antifriction and antiwear properties of TiO2 nanoparticles coated with oleic acid, TiO2-OA, as additives of a low viscosity polyalphaolefin base oil, PAO8. To find the optimal concentration of nanoadditives that minimize friction and wear, four PAO8 based nanodispersions were formulated: PAO8 + 0.10 wt% TiO2-OA, PAO8 + 0.25 wt% TiO2-OA, PAO8 + 0.35 wt% TiO2-OA and PAO8 + 0.50 wt% TiO2-OA. Tribological experiments were performed under pure sliding and rolling-sliding conditions at 120 °C, with the four formulated nanolubricants and with PAO8 base oil. All the nanolubricants showed lower friction coefficients than that obtained with the PAO8 base oil, reaching maximum reductions for the 0.35 wt% TiO2-OA nanolubricant, for both types of test conditions. The tribological specimens tested under pure sliding conditions with the nanolubricants showed fewer wear than those tested with PAO8, finding the highest wear decreases also with the PAO8 + 0.35 wt% TiO2-OA nanolubricant, being 26 %, 65 % and 73 %, in wear track width, depth and area, in that order. Through Raman microscopy and roughness study of the worn samples, it can be inferred that tribofilm, mending and polishing mechanisms occur. Moreover, the thermal conductivity of the optimal nanolubricant (0.35 wt%) was measured at 20, 30, 40 and 50 °CThis research is supported by Xunta de Galicia (ED431C 2020/10), by MCIN/AEI/10.13039/501100011033 through the PID2020-112846RB-C22 project and by LAETA, Portugal under project UID/50022/2020. JMLDR is grateful for financial support through the Margarita Salas programme, funded by MCIN/AEI/10.13039/501100011033 and “NextGenerationEU/PRTR”. FM acknowlegdes a IACOBUS grant to the European Grouping for Territorial Cooperation Galicia-Norte de Portugal (GNP-EGTC). Furthermore, authors also thank Repsol Lubricants for supplying us the PAO8 base oil and recognize the support of the RIAIDT-USC analytical skillsS

Tribological properties of hexagonal boron nitride nanoparticles or graphene nanoplatelets blended with an ionic liquid as additives of an ester base oil

Antifriction synergies between an ionic liquid (IL) and nanopowders as additives of an ester base oil were analysed at rolling conditions. For this aim, two nanodispersions based on hybrid combinations of hexagonal boron nitride nanoparticles (h-BN) or graphene nanoplatelets (GnP) with tri(butyl) ethylphosphonium diethylphosphate ionic liquid as additives in triisotridecyltrimellitate (TTM) base oil and the mixture of TTM and IL were analysed using two tribometer techniques. Film thickness characterisation and tribological tests were performed at rolling conditions [5% slide-roll-ratio (SRR)], under 50N and at operating temperatures of 30, 50 and 80°C. Stribeck curves showed that friction coefficients for the prepared lubricants are lower than those found for the TTM, being the best friction behaviour for the hybrid GnP nanolubricant. Furthermore, friction torque loss tests were performed in rolling ball bearings, observing that for the two hybrid nanolubricants lower friction torque values were obtainedThis work was supported by MINECO and the ERDF programme through ENE2017-86425-C2-2-R project, and by the Xunta de Galicia (ED431E 2018/08, ED431D 2017/06 and GRC ED431C 2020/10). JMLR acknowledges the IACOBUS programme for funding the research stay at the Porto UniversityS

919-8 High-speed Coronary Rotational Atherectomy. Are Angiographic Factors Predictive of Failure, Major Complications or Restenosis? A Multivariate Analysis

In order to determine if angiographic factors are predictive of Failure (F), Major Complications (Me) or Restenosis (R) after Rotational Atherectomy with Rotablator, 16 angiographic variables were analyzed in 243 coronary arteries of 228 patients using a multivariate logistic regression technique (quasi Newton method and maximal probability technique).F was defined as the impossibility to complete the procedure; MC as the occurrence of O-wave myocardial infarctiön, in-hospital death or the need for emergency bypass graft surgery; R as recurrent ischemia due to an angiographic reduction of the lumen of the culprit vessel within 6 months following the procedure.Angiographic variables analized were: 1: Vessel treated. 2: Type of obstruction (A-B-C Task Force AHA-ACC). 3: Lesion lenhgth. 4: Lesion eccentricity. 5: Lesion angulation. 6: Lesion calcification. 7: Ostial lesion. 8: Lesion at a bifurcation. 9: Restenosed lesion. 10: Preprocedural stenosis. 11’ Postatherectomy stenosis. 12: Final stenosis. 13: Difficult access. 14: Number of vessels diseased>70% (1 vessel/multiple vessels). 15: Ejection fraction (40%/>40%).16: Arterial diameter (<3 mm/>3 mm).Primary success rate was 95.5% (232/243 arteries) and MC rate was 1.7% (infarction 2 cases and coronary surgery 2 cases, no deaths were recorded). F occurred in 6 cases.None of the covariates analized was statistically significant for F or MC. R was observed in 28.3% of cases and was 1.86 times more likely in longer lesions (p<0.03) and 2.54 times more likely in non calcified lesions (p<0.04). When lesion length and the presence of calcium were associated in a logistic regression manner, the following was obtained:LengthCalciumRestenosis % probability<10mm+6.3%10-20 mm+11.1%>20mm+18.9%<10 mm-14.6%10-20 mm-24.2%>20mm-37.2Conclusions1) The angiographic variables considered were not prediclive of F or Me. 2) Restenosis ocurred more frequenlly in long and non calcified lesions

Interplay of Surface Diffusion and Surface Tension in the Evolution of Solid/Liquid Interfaces : Dealloying of β-Brass in Aqueous Sodium Chloride

The dealloying of β-brass in 0.5 M aqueous NaCl was studied by electrochemical techniques at different temperatures in the range 278 K ≤ T ≤ 318 K, complemented with in situ scanning tunneling microscopy (STM) imaging. In the potential region where the electrodissolution of zinc and the formation of vacancies and copper islands take place, two different roughness regimes were distinguished. When dealloying involves only a few monolayers (ML) the process approaches a quasiuniform alloy electrodissolution, whereas after electrodissolution of more than 20 ML, void formation takes place. In both regimes the interface evolution was analyzed by applying the dynamic scaling method to in situ STM imaging data. The first roughness regime exhibits a stable interface consisting of copper-rich islands that coarsen with time according to a surface diffusion controlled process. The second roughness regime exhibits an unstable interface due to a curvature dependent corrosion rate enhancing zinc electrodissolution at cavities. The overall interface evolution is well-described by a differential stochastic equation containing an electrodissolution term and surface rearrangement terms related to surface diffusion and negative surface tension effect.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Endocarditis en válvula aórtica nativa por Salmonella serotype Choleraesuis

Patient with a history of Chronic Myeloid Leukemia (CML) on day 10 postoperatively with respiratory distress and functional class decrease in addition to febrile peaks of 38.9 led to an allogeneic transplant of hematopoietic precursors, on physical examination presence of holosystolic murmur in the base, blood cultures with a positive report of S. choleraesuis 4 of 4, a transesophageal echocardiogram was taken showing vegetation filiform in the aortic valve with 12 mm without ejection fraction compromise and hemodynamic compromise, medical management with quinolones for 4 weeks was decided, achieving disappearance of the vegetation and murmur one week after medical treatment and negative blood cultures later.Se presenta el caso de un paciente con antecedente de Leucemia Mieloide Crónica (LMC) llevado a trasplante alogénico de precursores hematopoyéticos, en el día 10 postoperatorio refiere dificultad respiratoria y empeoramiento de clase funcional además de picos febriles de 38.9, al examen físico presencia de soplo holosistólico en focos de la base, realizan hemocultivos con reporte positivo de S. choleraesuis en 4 de 4, se toma ecocardiograma transesofágico donde se evidencia vegetación en válvula aórtica - valva semilunar posterior (no coronaria) de 12 mm filiforme sin condicionamiento de fracción de eyección -, por estabilidad clínica del paciente sin evidencia de compromiso hemodinámico se decide manejo médico con quinolonas por 4 semanas, logrando desaparición de la vegetación y del soplo a la semana de tratamiento médico y negativización de hemocultivos posteriores

Lubricant properties of trimethylolpropane trioleate biodegradable oil: High pressure density and viscosity, film thickness, Stribeck curves and influence of nanoadditives

Lubricant properties of trimethylolpropane trioleate synthetic base oil (TMPTO) were experimentally determined under different temperatures, pressures and rolling-sliding conditions. With the aim to obtain the viscosity-pressure coefficient, density and viscosity measurements were performed up to 150 MPa with a falling-body viscometer and a vibrating tube densimeter, respectively. Film thickness and friction properties were determined with a ball-on-disc apparatus from temperatures of 303.15 to 353.15 K, from slide-roll ratios from 5 to 50% at 50 N (applied load). Finally, it has also been evaluated if the use of nanoparticles as additives could involve changes on film thickness and Stribeck curves of TMPTO base oil. For this aim, hexagonal-boron nitride nanoparticles (h-BN) and graphene nanoplatelets (GnPs) were used at mass concentrations of 0.25, 0.5 and 1.0 wt%. The viscosity of TMPTO increases from 15 mPa s (at 10 MPa and 353.15 K) to 525 mPa s (at 150 MPa and 303.15 K). The Stribeck curves for TMPTO are placed between elastohydrodynamic and mixed lubrication. All nanolubricants show very similar Stribeck curves, being the lowest friction coefficient obtained for 0.25 wt% of GnP. It has been found that for most of the experimental conditions the addition of the GnP promotes an increase of the film thicknessSpanish Ministry of Economy and Competitiveness, the European Regional Development Fund programme and the Xunta de Galicia have supported this manuscript through ENE2017-86425-C2-2-R, GRC ED431C 2020/10 and ED431E 2018/08 projects. Dr. María J. G. Guimarey acknowledges a postdoctoral fellowship from the Xunta de Galicia (Spain) and the financial support from IACOBUS programmeS

Methodology for phytoplankton taxonomic group identification towards the development of a lab-on-a-chip

This paper presents the absorbance and fluorescence optical properties of various phytoplankton species, looking to achieve an accurate method to detect and identify a number of phytoplankton taxonomic groups. The methodology to select the excitation and detection wavelengths that results in superior identification of phytoplankton is reported. The macroscopic analyses and the implemented methodology are the base for designing a lab-on-a-chip device for a phytoplankton group identification, based on cell analysis with multi-wavelength lighting excitation, aiming for a cheap and portable platform. With such methodology in a lab-on-a-chip device, the analysis of the phytoplankton cells’ optical properties, e.g., fluorescence, diffraction, absorption and reflection, will be possible. This device will offer, in the future, a platform for continuous, autonomous and in situ underwater measurements, in opposition to the conventional methodology. A proof-of-concept device with LED light excitation at 450 nm and a detection photodiode at 680 nm was fabricated. This device was able to quantify the concentration of the phytoplankton chlorophyll a. A lock-in amplifier electronic circuit was developed and integrated in a portable and low-cost sensor, featuring continuous, autonomous and in situ underwater measurements. This device has a detection limit of 0.01 µ/L of chlorophyll a, in a range up to 300 µg/L, with a linear voltage output with chlorophyll concentration.European Regional Development Fund (ERDF) through the Interreg VA Spain-Portugal (POCTEP) 2014–2020 Program under grant agreement 0591_FOODSENS_1_E, under the national support to R&D units grant, through the reference project UIDB/04436/2020 and UIDP/04436/2020, and by project NORTE-08-5369-FSE-000039 co-founded by the European Social Fund FSE and through National funds NORTE 2020 and Regional Operacional Programa of North 2014/2020. The University of Vigo work was funded by a Xunta de Galicia grant to the Biological Oceanography Research Group (Consolidación e estruturación de unidades). This output reflects only the views of the authors, and the program authorities cannot be held responsible for any use that may be made of the information contained therei

Early Science with the Large Millimeter Telescope: COOL BUDHIES I - a pilot study of molecular and atomic gas at z~0.2

An understanding of the mass build-up in galaxies over time necessitates tracing the evolution of cold gas (molecular and atomic) in galaxies. To that end, we have conducted a pilot study called CO Observations with the LMT of the Blind Ultra-Deep H I Environment Survey (COOL BUDHIES). We have observed 23 galaxies in and around the two clusters Abell 2192 (z = 0.188) and Abell 963 (z = 0.206), where 12 are cluster members and 11 are slightly in the foreground or background, using about 28 total hours on the Redshift Search Receiver (RSR) on the Large Millimeter Telescope (LMT) to measure the $^{12}$CO J = 1 --> 0 emission line and obtain molecular gas masses. These new observations provide a unique opportunity to probe both the molecular and atomic components of galaxies as a function of environment beyond the local Universe. For our sample of 23 galaxies, nine have reliable detections (S/N$\geq$3.6) of the $^{12}$CO line, and another six have marginal detections (2.0 < S/N < 3.6). For the remaining eight targets we can place upper limits on molecular gas masses roughly between $10^9$ and $10^{10} M_\odot$. Comparing our results to other studies of molecular gas, we find that our sample is significantly more abundant in molecular gas overall, when compared to the stellar and the atomic gas component, and our median molecular gas fraction lies about $1\sigma$ above the upper limits of proposed redshift evolution in earlier studies. We discuss possible reasons for this discrepancy, with the most likely conclusion being target selection and Eddington bias.Comment: MNRAS, submitte