Estudio de la influencia del sistema de referencia en la evaluación de parámetros de acabado superficial

In the present paper the influence of the reference system with regard to the characterization of the surface finishing is analyzed. The effect of the reference system’s choice on the most representative surface finishing parameters (e.g. roughness average Ra and root mean square values Rq) is studied. The study can also be applied to their equivalent parameters in waviness and primary profiles. Based on ISO and ASME standards, three different types of regression lines (central, mean and orthogonal) are theoretically and experimentally analyzed, identifying the validity and applicability fields of each one depending on profile’s geometr

Effect of the Reference Line on Main Roughness Parameters

In the present paper the influence of the reference system with regard to the characterization of the surface finishing is analyzed. The effect of the reference system’s choice on the most representative surface finishing parameters (e.g. roughness average Ra and root mean square values Rq) is studied. The study can also be applied to their equivalent parameters in waviness and primary profiles. Based on ISO and ASME standards, three different types of regression lines (center, mean and orthogonal) are theoretically and experimentally analyzed, identifying the validity and applicability fields of each one depending on profile’s geometry

Study of the Influence of Reference System in Surface Finishing Parameters Evaluation.

In the present paper the influence of the reference system with regard to the characterization of the surface finishing is analyzed. The effect of the reference system’s choice on the most representative surface finishing parameters (e.g. roughness average Ra and root mean square values Rq) is studied. The study can also be applied to their equivalent parameters in waviness and primary profiles. Based on ISO and ASME standards, three different types of regression lines (central, mean and orthogonal) are theoretically and experimentally analyzed, identifying the validity and applicability fields of each one depending on profile’s geometry. El presente trabajo realiza un estudio de la influencia que supone la elección del sistema de referencia en la determinación los valores de los parámetros más relevantes empleados en la caracterización del acabado superficial tales como la rugosidad media aritmética Ra o la rugosidad media cuadrática Rq y sus equivalentes en los perfiles de ondulación y completo. Partiendo de la definición establecida por las normas ISO y ASME, se analizan tres tipos de líneas de regresión cuadrática (línea central, línea media y línea ortogonal), delimitando los campos de validez y de aplicación de cada una de ellas en función de la geometría del perfil. Para ello se plantean diversos tipos de perfiles y se desarrolla un estudio teórico y experimental de los mismos

New lanthanide phosphonates structures obtained using XRPD data

5 páginas, 2 figuras, 3 tablas.-- Trabajo presentado como póster a la 12th European Powder Diffraction Conference (EPDIC 2010).-- et al.Seven lanthanide diphosphonates, [H3N(CH2)4NH3]Ln[hedpH][hedpH2] (Ln = La, Pr, Sm, Eu, Gd, Tb, Er; hedp = 1 hydroxyethylidenediphosphonate) have been synthesized with 1,4-diaminobutane as the template. The structures were obtained starting from the known X-ray single crystal model of lanthanum compound, with the X-ray powder diffraction data for these seven compounds. H-atoms were introduced using geometrical considerations. Rietveld fits of the experimental diffractograms confirm the isostructurality of all compounds in the series, and show the different behaviour between the two distances M-M existing in the structures.Financial support from Spanish MICINN (MAT2006-01997, MAT2010-15095 and ‘Factoría de Cristalización’ Consolider Ingenio 2010), Un-iversidad de Oviedo and Banco Santander is acknowledged. FEDER support is also acknowledged.Peer reviewe

Bis(2,2′-bipyridyl-κ2 N,N′)dichlorido­rhodium(III) perchlorate

The asymmetric unit of the title compound, [RhCl2(C10H8N2)2]ClO4, consists of one unit of the cationic complex [RhCl2(bipy)2]+ and one uncoordinated perchlorate anion. The RhIII atom is coordinated by four N atoms from two bipyridyl ligands and two Cl atoms, forming a distorted octa­hedral environment. The Cl ligands are cis. Two intramolecular C—H⋯Cl hydrogen bonds occur in the cationic complex . In the crystal, mol­ecules are linked together by a hydrogen-bond network involving the H atoms of bipyridyl rings and perchlorate anions. An O atom of the perchlorate anion is disordered over two sites, with an occupancy-factor ratio of 0.78 (3):0.22 (3)

HYDI-DSI revisited: Constrained non-parametric EAP imaging without q-space re-gridding

Producción CientíficaHybrid Diffusion Imaging (HYDI) was one of the first attempts to use multi-shell samplings of the q-space to infer diffusion properties beyond Diffusion Tensor Imaging (DTI) or High Angular Resolution Diffusion Imaging (HARDI). HYDI was intended as a flexible protocol embedding both DTI (for lower -values) and HARDI (for higher -values) processing, as well as Diffusion Spectrum Imaging (DSI) when the entire data set was exploited. In the latter case, the spherical sampling of the q-space is re-gridded by interpolation to a Cartesian lattice whose extent covers the range of acquired b-values, hence being acquisition-dependent. The Discrete Fourier Transform (DFT) is afterwards used to compute the corresponding Cartesian sampling of the Ensemble Average Propagator (EAP) in an entirely non-parametric way. From this lattice, diffusion markers such as the Return To Origin Probability (RTOP) or the Mean Squared Displacement (MSD) can be numerically estimated. We aim at re-formulating this scheme by means of a Fourier Transform encoding matrix that eliminates the need for q-space re-gridding at the same time it preserves the non-parametric nature of HYDI-DSI. The encoding matrix is adaptively designed at each voxel according to the underlying DTI approximation, so that an optimal sampling of the EAP can be pursued without being conditioned by the particular acquisition protocol. The estimation of the EAP is afterwards carried out as a regularized Quadratic Programming (QP) problem, which allows to impose positivity constraints that cannot be trivially embedded within the conventional HYDI-DSI. We demonstrate that the definition of the encoding matrix in the adaptive space allows to analytically (as opposed to numerically) compute several popular descriptors of diffusion with the unique source of error being the cropping of high frequency harmonics in the Fourier analysis of the attenuation signal. They include not only RTOP and MSD, but also Return to Axis/Plane Probabilities (RTAP/RTPP), which are defined in terms of specific spatial directions and are not available with the former HYDI-DSI. We report extensive experiments that suggest the benefits of our proposal in terms of accuracy, robustness and computational efficiency, especially when only standard, non-dedicated q-space samplings are available.Ministerio de Ciencia e Innovación (PID2021-124407NB-I00 and TED2021-130758B-I00)Ministry of Science and Higher Education (Poland) (PPN/BEK/ 2019/1/00421

Correlates between morphology, diet and foraging mode in the Ladder Snake Rhinechis scalaris (Schinz, 1822)

In many vertebrates, foraging mode (active versus sit-and-wait) is tied to some traits of their natural history such as morphology, type of prey, rate of food acquisition, and survival rate. We explore the correlates between some morphological traits of a Mediterranean colubrid and its feeding ecology and the predation risk, by comparing data on teeth number, tail damage, and diet. A large sample (n = 368) of the Ladder Snake, Rhinechis scalaris is used. The species feeds almost exclusively on endotherms, mainly mammals (nearly 95% of the diet in mass), which set R. scalaris among the most stenophagous snakes in the western Palaearctic. There is also a high percentage of motionless prey in the diet (up to 50% in prey mass), such as nestling birds, mammals and bird eggs. The species is so canalised to a diet based on endotherms that it does not follow the general rule in medium-sized snakes of an ontogenetic dietary shift from ectothermic to endothermic prey; juveniles consumed the smallest endothermic animals: nestling small-mammals. The number of maxillary teeth (mean 15.1), the lowest within the former and large genus Elaphe, is likely related to its trophic specialization. Rhinechis scalaris also faces an elevated risk of predation, something general in active searcher snakes compared to ambush foragers, as revealed by many individuals with damaged tails (19.9%), the highest within the Iberian community of snakes. We conclude from indirect evidence (high predation on stationary prey, many individuals with damaged tails) that the species is an active searcher and that this foraging mode influences other natural-history traits (i.e. reproductive habits).The last stage of this study was supported by the Research Award REN2000-1376 GLO of the Spanish MCYT to the senior author and to MF

Assessment of natural radioactivity levels and radiation exposure in new building materials in Spain

Novel building materials were manufactured and analyzed for 226Ra, 232Th and 40K using an HPGe gamma-ray spectrometer. The results show that the highest value of 40K was 4530 Bq per kg which was measured in a sample containing fly ashes from olive stones. The highest values of 226Ra and 232Th activities were 181 and 185 Bq per kg, which were measured in a sample with fly ashes from the co-combustion of coal and coke, respectively. On the other hand, the lowest values of 40K, 226Ra and 232Th activities were obtained for samples incorporating mussel shells. The radiological health hazard parameters, such as radium equivalent activity (Raeq), activity concentration index (I), absorbed and effective dose rates, associated with these radionuclides were evaluated. These values are within the EU recommended limits in building materials, except for samples of concrete containing fly ashes from olive stones, coal and coke. This study has contributed to the inclusion of industrial wastes that have not been collected previously in the Naturally Occurring Radioactive Material (NORM) databases on radioactivity of building materials

Techno-economic feasibility of ionic liquids-based CO2 chemical capture processes

A techno-economic assessment of Ionic Liquids (ILs)-based post-combustion, biogas and pre-combustion CO2 chemical capture processes was carried out using Aspen Plus and Aspen Process Economic Analyzer (APEA). This cost estimation procedure is newly integrated to our COSMO-based/Aspen Plus methodology used to design the chemical absorption processes with 90% of CO2 capture. The equipment investment and variable operating cost were analyzed relating to the process operating conditions and the IL performance. The total annualized cost was used as the index to economically evaluate the processes at three CO2 treatment capacities and employing three different ILs: [P2228][CNPyr], [P66614][CNPyr] and [Bmim][acetate]. It benefits from economy of scale as well as it is directly related to both IL enthalpy of reaction and process gap capacity, being [P2228][CNPyr] -which has the most exothermic reaction and highest gap capacity- the solvent achieving the lowest costs. Current results indicate that operating at vacuum pressure to better regenerate the IL entails a remarkable cost penalty. Hence, both capital (CAPEX) and operational expenses (OPEX) could be reduced to achieve a total cost of 81.32 $/tCO2 for [P2228][CNPyr] in post-combustion CO2 capture when regenerating the IL at atmospheric pressure and 121.5 °C. Three IL pricing basis were considered when calculating the solvent cost. A conservative IL scaled up price of 50$/kg only increments around 5% the total annualized cost of the processThe authors are grateful to Ministerio de Economía y Competitividad of Spain (project CTQ2017-89441-R) and Comunidad de Madrid (project P2018/EMT4348) for financial support and Centro de Computación Científica de la Universidad Autónoma de Madrid for computational facilitie

Investigation of inertia response and rate of change of frequency in low rotational inertial scenario of synchronous dominated system

The shift to a sustainable energy future is becoming more reliant on large-scale deployment of renewable and distributed energy resources raising concerns about frequency stability. Rate of Change of Frequency (RoCoF) is necessary as a system inertia metric in order for network operators to perform control steps to preserve system operation. This paper presents in a straightforward and illustrative way several relevant aspects of the inertia response and RoCoF calculation that could help to understand and explain the implementation and results of inertial response controllers on power converter-based technologies. Qualitative explanations based on illustrative numerical experiments are used to cover the effects on the system frequency response of reduced rotational inertia in synchronous dominated power systems. One main contribution of this paper is making evident the importance of the governor action to avoid the synchronous machine taking active power from the system during the recovering period of kinetic energy in an under frequency event