A new approach for time-space wear modeling applied to machining tool wear

A general methodology is proposed and demonstrated for modeling the progression of crater wear on cutting tools used for steel machining. Dimensional analysis and Finite Element Analysis of metal cutting are the foundations of this new approach. The dimensional analysis resulted in a differential equation which describes wear rate as a function of dimensionless variables. Numerical models of cutting allow one to estimate local variables associated with wear at tool-chip contact. Orthogonal cutting simulations were carried out with commercial code DEFORM - 2D Ver 11.0. AISI 1018 steel was used as the workpiece material for an uncoated carbide cutting tool. Prediction of wear evolution and crater profiles on the tool's rake face were in good agreement with experimental data.This work was supported by Secretaría Nacional de Educación Superior, Ciencia y Tecnología del Ecuador – SENESCYT, Universidad Carlos III de Madrid and the Spanish Ministry of Economy and Competitiveness and FEDER Program under Grant DPI2014-56137-C2-2-R.Publicad

Nutrient limitation suppresses the temperature dependence of phytoplankton metabolic rates

Climate warming has the potential to alter ecosystem function through temperature-dependent changes in individual metabolic rates. The temperature sensitivity of phytoplankton metabolism is especially relevant, since these microorganisms sustain marine food webs and are major drivers of biogeochemical cycling. Phytoplankton metabolic rates increase with temperature when nutrients are abundant, but it is unknown if the same pattern applies under nutrient-limited growth conditions, which prevail over most of the ocean. Here we use continuous cultures of three cosmopolitan and biogeochemically relevant species (Synechococcus sp., Skeletonema costatum and Emiliania huxleyi) to determine the temperature dependence (activation energy, Ea) of metabolism under different degrees of nitrogen (N) limitation. We show that both CO2 fixation and respiration rates increase with N supply but are largely insensitive to temperature. Ea of photosynthesis (0.11 ± 0.06 eV, mean ± SE) and respiration (0.04 ± 0.17 eV) under N-limited growth is significantly smaller than Ea of growth rate under nutrient-replete conditions (0.77 ± 0.06 eV). The reduced temperature dependence of metabolic rates under nutrient limitation can be explained in terms of enzyme kinetics, because both maximum reaction rates and half-saturation constants increase with temperature. Our results suggest that the direct, stimulating effect of rising temperatures upon phytoplankton metabolic rates will be circumscribed to ecosystems with high-nutrient availabilityMinisterio de Economía y Competitividad | Ref. CTM2014-53582-

Respuesta hipofisaria y ovulatoria de conejas nulíparas alimentadas con dietas suplementadas con ácidos grasos poliinsaturados n-3.

Veinte conejas nulíparas se alimentaron ad libitum desde las 10 a las 16 semanas de edad con dos piensos isofibrosos, isoenergéticos e isoproteicos suplementados con dos fuentes de grasa diferentes: 0,75% de manteca para la dieta control (grupo C; n=10) ó 1,5% de un suplemento (Optomega-50; Optivite International Ltd., España) que contenía un 50% de extracto etérero y 38% de ácidos grasos poli-insaturados n-3 (AG n-3) para la dieta experimental (grupo P; n=10). A las 16 semanas de edad se determinó el consumo de pienso, así como la tasa de ovulación y las concentraciones plasmáticas de progesterona y LH a 0, 60 min, 5, 7 y 9 días post-inducción de ovulación con 20 μg de Gonadorelina (Inducel-GnRH, Lab. Ovejero). El consumo de pienso (150,5 g/d), el pico preovulatorio de LH (149,7±10,9 ng/ml), la tasa de ovulación (95%) y el número de cuerpos lúteos (9,8±0,7) fueron similares entre tratamientos. Las concentraciones plasmáticas de progesterona aumentaron a los 60 minutos (7,13±19 ng/ml) y 5 días (13,3±1,9 ng/ml) con respecto al día 0 (0,7±1,9 ng/ml; P<0.05), permaneciendo elevadas el día 9 en ambos grupos (19,4±1,9 ng/ml). Además, el día 5 y 7 post-inducción, las hembras alimentadas con la dieta P tendieron a tener niveles más elevados de progesterona en sangre que las alimentadas con la dieta C (16,6±1,9 vs.12,6±1,8 y 19,0±1,8 vs. 15,5±2,1 ng/ml, P=0,068 y P=0,082; respectivamente) que coinciden con el momento de la implantación embrionaria en esta especie. Por lo tanto, la suplementación con AG n-3 podría mejorar los niveles de progesterona en sangre y por lo tanto reducir la mortalidad embrionaria en este punto

Cosmology of a brane radiating gravitons into the extra dimension

We study in a self-consistent way the impact of the emission of bulk gravitons on the (homogeneous) cosmology of a three-brane embedded in a five-dimensional spacetime. In the low energy regime, we recover the well known result that the bulk affects the Friedmann equation only via a radiation-like term \C/a^4, called dark or Weyl radiation. By contrast, in the high energy regime, we find that the Weyl parameter \C is no longer constant but instead grows very rapidly as \C\propto a^4. As a consequence, the value of \C today is not a free parameter as usually considered but is a fixed number, which, generically, depends only on the number of relativistic degrees of freedom at the high/low energy transition. Our estimated amount of Weyl radiation satisfies the present nucleosynthesis bounds.Comment: 12 page

Blockchain Architecture Based on Decentralised PoW Algorithm

Blockchain has gained increasing popularity across various industries due to its decentralized, stable, and secure nature. Consensus algorithms play a crucial role in maintaining the security and efficiency of Blockchain systems and selecting the right algorithm can lead to significant performance improvements. This article aims to provide a comparative review of the most used Blockchain consensus algorithms, highlighting their strengths and weaknesses. Additionally, we propose a dissociated architecture for an efficient Blockchain system that doesn't compromise on security. A comparison is made between this architecture and the reviewed algorithms, considering aspects such as algorithm performance, energy consumption, mining, decentralization level, and vulnerability to security threats. The research findings demonstrate that the proposed architecture can support complex algorithms with high security while addressing issues related to efficiency, processing performance, and energy consumption

Understanding the importance of animation in human-computer interfaces and its relation to user experience

Animation is increasingly used in multimedia user interfaces (UI). Ever more applications are including animation to improve their UI and user experience (UX). Animation seems to play a key role to develop user-friendly, easy-to-use and easy-to-understand apps that achieve a satisfactory UX. This work attempts to explain animation performance in multimedia UI and how this affects the UX. We found that: (1) animation is a key element of multimedia UI that strongly affects UX and can improve it, if applied correctly; (2) animation enhances: reduced perceived waiting time, explanatory and cognitive support, efficient feedback and increased user attention; (3) animation's major properties lie in adapting its intensity, function, time and aesthetics to the context of action. Additionally, we identified two categories of animation aspects in multimedia UI: internal aspects and external features. Furthermore, this study demonstrates that the design of animated multimedia interfaces does not have a standardised methodology. Animation is incorporated ad-hoc, under the individual empirical experience of the creators, and without any a priori guarantee of usefulness or success. Therefore, our future work aims to generate an integral model where the variables related to animation in multimedia UI that modulate UX are analysed, and thus improve human-computer interfaces

Digestibilidad y respuesta ovárica de conejas reproductoras alimentadas con dietas suplementadas con ácidos grasos poliinsaturados n-3

Aumentar el número de gazapos destetados por coneja y parto es un objetivo importante para incrementar la rentabilidad del sector cunícola industrial con efectos directos. La mejora genética de la prolificidad en las líneas de madres ha demostrado ser una estrategia eficaz para alcanzar este objetivo; sin embargo otras vías, como la influencia de diferentes fuentes de grasa en las dietas de conejas reproductoras, han sido muy poco estudiadas. Los ácidos grasos (AG) n-3 interfieren en la fisiología reproductiva porque pueden modular las enzimas involucradas en el metabolismo de las prostaglandinas y del colesterol que es el precursor de los esteroides como la progesterona (revisado en Gulliver et al., 2012). El objetivo de este trabajo es estudiar si la suplementación con AG poliinsaturados (PUFA) n-3 de las dietas de conejas durante la recría puede afectar a la tasa de ovulación y a la síntesis esteroidogénica ovárica determinada mediante las concentraciones de progesterona plasmática

Estudio inicial de la estructura genética del conejo ibicenco a aprtir de información genealógica.

Aumentar el número de gazapos destetados por coneja y parto es un objetivo importante para incrementar la rentabilidad del sector cunícola industrial con efectos directos. La mejora genética de la prolificidad en las líneas de madres ha demostrado ser una estrategia eficaz para alcanzar este objetivo; sin embargo otras vías, como la influencia de diferentes fuentes de grasa en las dietas de conejas reproductoras, han sido muy poco estudiadas. Los ácidos grasos (AG) n-3 interfieren en la fisiología reproductiva porque pueden modular las enzimas involucradas en el metabolismo de las prostaglandinas y del colesterol que es el precursor de los esteroides como la progesterona (revisado en Gulliver et al., 2012). El objetivo de este trabajo es estudiar si la suplementación con AG poliinsaturados (PUFA) n-3 de las dietas de conejas durante la recría puede afectar a la tasa de ovulación y a la síntesis esteroidogénica ovárica determinada mediante las concentraciones de progesterona plasmática

Nuclear factor-kappa B in the liver of patients with chronic hepatitis C: decreased RelA expression is associated with enhanced fibrosis progression

The mechanisms of liver damage in chronic hepatitis C virus (HCV) infection are poorly understood. The transcription factor, nuclear factor-kappa B (NF-kappa B), regulates the expression of genes involved in apoptosis, inflammation, and antiviral response. It plays a protective role in several forms of liver damage. In this study, we analyzed NF-kappa B by gel mobility shift assay and immunohistochemistry in liver biopsies from HCV-infected patients, and we have determined the hepatic levels of the components of the NF-kappa B system by semiquantitative polymerase chain reaction (PCR). We found that NF-kappa B was activated in the liver of patients with chronic hepatitis C. Neither NF-kappa B activity nor the RNA levels of NF-kappa B subunits showed correlation with liver inflammatory activity, viral load, or HCV genotype. By contrast, hepatic mRNA values of RelA, the main element of active NF-kappa B, correlated inversely with apoptosis (r = -.68; P <.05) and with the rate of fibrosis progression (r = -.51; P <.04). In intermediate/rapid fibrosers, RelA mRNA levels were significantly decreased as compared with slow fibrosers (P <.003) and with normal livers (P <.03). In conclusion, we found that NF-kappa B is activated in chronic HCV-infected livers, and that the expression of RelA is inversely correlated with liver cell apoptosis and with the rate of fibrosis progression. Our data thus suggest that RelA expression may protect against liver fibrosis and hepatocellular damage

Influence of production system and finishing feeding on meat quality of Rubia Gallega calves

Aim of study: Beef quality is mainly affected by finishing feeding (FF) and production system (PS). The effects of PS (extensive, semi-extensive, traditional and intensive systems) and FF from Rubia Gallega calves were compared in terms of meat quality.Area of study: Galicia (NW Spain)Material and methods: Calves (n=10 per treatment) were slaughtered at nine months of age and meat samples were assessed in terms of meat quality attributes such as physicochemical, nutritional and sensory analysis performed by a trained panel.Main results: Meat chemical composition varied (p&lt;0.01) with PS and FF. The semi-extensive system showed the lowest values (p&lt;0.05) for cooking loss (22.8%) and for shear force (26.0 N) while the extensive system presented the lowest contents of saturated fatty acids (SFA) and the highest contents of linolenic acid (p&lt;0.001). The SFA and polyunsaturated fatty acid (PUFA) contents varied with FF (p&lt;0.05). The lowest and highest values for SFA and PUFA were displayed in extensive group finished with Pasture/Concentrate, meanwhile feedlot group finished with Concentrate/Straw showed and opposite trend. The n-6/n-3 ratio was lower than 4 for extensive and semi-extensive systems (p&lt;0.001). In addition, tenderness and juiciness showed significant differences mainly due to FF.Research highlights: This study showed that meat of calves reared in extensive systems was the healthiest, regarding total fat and fatty acid composition. It can be concluded that finishing feeding, and PS affected meat quality. Hence the potential usefulness of these results is to improve meat quality and safety according to market demands