806 research outputs found
Multi-objective optimization of the geometry of a double wishbone suspension system
The vehicle suspension system optimal design problem is multi-objective, has a hierarchical multi-level structure and presents couplings with the rest of the vehicle design. Moreover, many of the vehicle performances are dependent of the suspension system, specifically on its geometry. For this reason, it is desirable to develop a strategy in which the geometry of the suspension system is automatically generated with optimal characteristics. For this type of problems, the Analytical Target Cascading (ATC) brings a powerful optimization strategy that permits the management of a complex optimal design problem in a partitioned manner. This work proposes a new approach for the automatic optimal geometry generation of the suspension system of the vehicle, the development of the optimization problem in order to use the ATC optimization strategy and a case study in which a full-scale functional prototype is designed with the use of the developed tools
Design of a 200kW electric powertrain for a high performance electric vehicle
With the purpose of designing the electric powertrain of a high performance electric vehicle capable of running a quarter mile in 10 seconds, firstly it is necessary to calculate the required energy, torque, and power in order to size and select the suitable storage components and electric motors. Secondly, an assessment of the powertrain arrangement is needed to choose the best internal configuration of the vehicle and guarantee the highest efficiency possible. Finally, a design of the power conversion stages, specifically the DC-DC converter that interfaces the storage unit with the electric motors, is required as well. This paper shows the energy calculation procedure based on a longitudinal dynamic model of the vehicle and the selection method of the storage components and motors needed for this application, as well as the design of two 100kW interleaved boost converters with coupled inductors. In addition, a novel operation of the interleaved boost converter is proposed in order to increase the efficiency of the converter. As a result, the designed converter achieved a power density of 24,2kW/kg with an efficiency of 98 %, which was validated by experimental tests of a low power prototype.Para diseñar el tren de potencia de un vehículo eléctrico de alto desempeño capaz de correr un cuarto de milla en 10 segundos, primero es necesario calcular la potencia y energía necesarias para dimensionar y seleccionar los componentes de almacenamiento y los motores adecuados. Segundo, se requiere una evaluación de varios trenes de potencia para seleccionar la mejor configuración interna del vehículo con el propósito de garantizar la mayor eficiencia posible. Finalmente, se necesita un diseño del convertidor de potencia DC-DC que haga la interfaz entre la unidad de almacenamiento y los motores eléctricos con sus respectivos inversores. Este artículo presenta el procedimiento para el cálculo de la energía necesaria para correr el vehículo con base en un modelo dinámico longitudinal. Así mismo, se presenta el método de selección de los componentes de almacenamiento de energía necesarios. Finalmente, se presenta el diseño de dos convertidores intercalados con inductores acoplados de 100kW operando bajo una novedosa operación propuesta para incrementar la eficiencia del convertidor. Como resultado, el convertidor diseñado logró una densidad de potencia de 24,2kW/kg y una eficiencia de 98%, la cual es validada con pruebas experimentales de un prototipo de baja potencia
LiNi0.5Mn1.5O4 Thin Films Grown by Magnetron Sputtering under Inert Gas Flow Mixtures as High-Voltage Cathode Materials for Lithium-Ion Batteries
Delivering a commercial high-voltage spinel LiNi0.5Mn1.5O4 (LNMO) cathode electrode for Li-ion batteries would result in a significant step forward in terms of energy density. However, the structural ordering of the spinel and particle size have considerable effects on the cathode material's cyclability and rate capability, which are crucial challenges to address. Here, a novel mid-frequency alternating current dual magnetron sputtering method was presented, using different Ar-N-2 gas mixtures ratios for the process gas to prepare various LNMO thin films with highly controlled morphology and particle size; as determined from X-ray diffraction, Raman spectroscopy and electron microscopy. It resulted in enhanced cycling and rate performance. This processing method delivered N-containing LNMO thin film electrodes with up to 15 % increased discharge capacity at 1 C (120 mAh g(-1)) with respect to standard LNMO (grown under only Ar gas flow) thin film electrodes, along with outstanding rate performance up to 10 C (99 mAh g(-1)) in the operating voltage window 3.5-4.85 V vs. Li+/Li. Besides, electrochemical impedance spectroscopy results showed that the intricate phase transitions present in standard LNMO electrodes were almost suppressed in N-containing LNMO thin films grown under different Ar-N-2 gas flow mixtures
Music Intervention Approaches for Alzheimer’s Disease: A Review of the Literature
Music interventions have been widely adopted as a potential non-pharmacological therapy for patients with Alzheimer’s disease (AD) to treat cognitive and/or behavioral symptoms of the disease. In spite of the prevalence of such therapies, evidence for their effectiveness report mixed results in the literature. The purpose of this narrative review is to investigate the effectiveness of various intervention strategies (music therapy vs. music listening techniques) and music type used in the intervention (individualized vs. non-individualized music) on cognitive and behavioral outcomes for persons with AD. Databases were searched for studies using either active music therapy or music listening techniques over the last 10 years. These studies were in English, included persons with AD dementia, and whose protocol gathered pre- and post-intervention outcome measures. We initially identified 206 papers which were then reduced to 167 after removing duplicates. Further review yielded 13 papers which were extensively reviewed, resulting in a final sample of six papers. Our analysis of these papers suggested that, regardless of the music intervention approach, individualized music regimens provided the best outcomes for the patient. Furthermore, music listening may act as a relaxation technique and therefore provide a long-term impact for the patient, while active music therapy may acts to engage participants through social interaction and provide acute benefits. Our findings suggest that music techniques can be utilized in various ways to improve behavior and cognition
CRP/anti-CRP Antibodies Assembly on the Surfaces of Cell Remnants Switches Their Phagocytic Clearance Toward Inflammation
Systemic lupus erythematosus (SLE) is a chronic inflammatory disease characterized by the production of autoantibodies, formation of immune complexes (IC), and activation of complement that ultimately fuel acute and/or chronic inflammation. Accumulation in blood and tissues of post-apoptotic remnants is considered of etiological and pathological importance for patients with SLE. Besides receptors directly recognizing apoptotic cells, soluble opsonins of the innate immune system bind apoptotic material dependent on the stage of apoptosis. We describe the binding to the surface of secondary necrotic cells (SNEC) of the serum opsonin CRP and further opsonins. We show that anti-dsDNA and anti-CRP autoantibodies bind and sensitize SNEC. Autoantibody-sensitized SNEC were cleared by macrophages in vitro and induced a pro-inflammatory cytokine response. In conclusion, anti-CRP, CRP, and SNEC form a ternary pyrogen endowed with strong pro-inflammatory capabilities which is able to maintain and perpetuate chronic inflammation
Mid-infrared Galaxy Morphology from the Spitzer Survey of Stellar Structure in Galaxies (S^4G): The Imprint of the De Vaucouleurs Revised Hubble-Sandage Classification System at 3.6 μm
Spitzer Space Telescope Infrared Array Camera imaging provides an opportunity to study all known morphological types of galaxies in the mid-IR at a depth significantly better than ground-based near-infrared and optical images. The goal of this study is to examine the imprint of the de Vaucouleurs classification volume in the 3.6 μm band, which is the best Spitzer waveband for galactic stellar mass morphology owing to its depth and its reddening-free sensitivity mainly to older stars. For this purpose, we have prepared classification images for 207 galaxies from the Spitzer archive, most of which are formally part of the Spitzer Survey of Stellar Structure in Galaxies (S^4G), a Spitzer post-cryogenic ("warm") mission Exploration Science Legacy Program survey of 2331 galaxies closer than 40 Mpc. For the purposes of morphology, the galaxies are interpreted as if the images are blue light, the historical waveband for classical galaxy classification studies. We find that 3.6 μm classifications are well correlated with blue-light classifications, to the point where the essential features of many galaxies look very similar in the two very different wavelength regimes. Drastic differences are found only for the most dusty galaxies. Consistent with a previous study by Eskridge et al., the main difference between blue-light and mid-IR types is an ≈1 stage interval difference for S0/a to Sbc or Sc galaxies, which tend to appear "earlier" in type at 3.6 μm due to the slightly increased prominence of the bulge, the reduced effects of extinction, and the reduced (but not completely eliminated) effect of the extreme population I stellar component. We present an atlas of all of the 207 galaxies analyzed here and bring attention to special features or galaxy types, such as nuclear rings, pseudobulges, flocculent spiral galaxies, I0 galaxies, double-stage and double-variety galaxies, and outer rings, that are particularly distinctive in the mid-IR
Specific genetic markers for detecting subtypes of dengue virus serotype-2 in isolates from the states of Oaxaca and Veracruz, Mexico
<p>Abstract</p> <p>Background</p> <p>Dengue (DEN) is an infectious disease caused by the DEN virus (DENV), which belongs to the <it>Flavivirus </it>genus in the family <it>Flaviviridae</it>. It has a (+) sense RNA genome and is mainly transmitted to humans by the vector mosquito <it>Aedes aegypti</it>. Dengue fever (DF) and dengue hemorrhagic fever (DHF) are caused by one of four closely related virus serotypes (DENV-1, DENV-2, DENV-3 and DENV-4). Epidemiological and evolutionary studies have indicated that host and viral factors are involved in determining disease outcome and have proved the importance of viral genotype in causing severe epidemics. Host immune status and mosquito vectorial capacity are also important influences on the severity of infection. Therefore, an understanding of the relationship between virus variants with altered amino acids and high pathogenicity will provide more information on the molecular epidemiology of DEN. Accordingly, knowledge of the DENV serotypes and genotypes circulating in the latest DEN outbreaks around the world, including Mexico, will contribute to understanding DEN infections.</p> <p>Results</p> <p>1. We obtained 88 isolates of DENV, 27 from Oaxaca and 61 from Veracruz. 2. Of these 88 isolates, 16 were serotype 1; 62 serotype 2; 7 serotype 3; and 2 serotype 4. One isolate had 2 serotypes (DENV-2 and -1). 3. Partial nucleotide sequences of the genes encoding C- prM (14 sequences), the NS3 helicase domain (7 sequences), the NS5 S-adenosyl methionine transferase domain (7 sequences) and the RNA-dependent RNA polymerase (RdRp) domain (18 sequences) were obtained. Phylogenetic analysis showed that DENV-2 isolates belonged to the Asian/American genotype. In addition, the Asian/American genotype was divided into two clusters, one containing the isolates from 2001 and the other the isolates from 2005–2006 with high bootstrap support of 94%.</p> <p>Conclusion</p> <p>DENV-2 was the predominant serotype in the DF and DHF outbreak from 2005 to 2006 in Oaxaca State as well as in the 2006 outbreak in Veracruz State, with the Asian/American genotype prevalent in both states. Interestingly, DENV-1 and DENV-2 were the only serotypes related to DHF cases. In contrast, DENV-3 and DENV-4 were poorly represented according to epidemiological data reported in Mexico. We found that isoleucine was replaced by valine at residue 106 of protein C in the isolates from these 2005–2006 outbreaks and in those from the 1997, 1998 and 2001 outbreaks in the Caribbean islands. We suggested that this amino acid change may be used as a signature for isolates arising in the Caribbean islands and pertaining to the Asian/American genotype. Other amino acid changes are specific for the Asian/American, Asian and American strains.</p
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