bluuebunny/crossref_metadata_2025 huggingface dataset:
Acute and Subchronic (28-day) Oral Toxicity Studies on the Film Formulation of k-Carrageenan and Konjac Glucomannan for Soft Capsule Application
Authors: Sutrisni Ni Nyoman Wiwik , Soewandhi Sundani Nurono , Adnyana I Ketut , Sasongko Lucy D N
Published: April 2019

The aim of this study was to investigate the acute and subchronic toxicity of a film formulation that combines κ-Carrageenan and konjac glucomannan for soft capsule application. For the acute toxicity study, a dose of 2000 mg/kg body weight (bw) of the film suspension was administered orally to rats. The animals were observed for toxic symptoms and mortality daily for 14 days. In a subchronic toxicity study, the film suspension, at doses of 10, 30 and 75 mg/kg bw for 28 days, were orally administered to rats. After 28 days, the rats were sacrificed for hematological, biochemical and histological examination. In the acute toxicity study, neither signs of toxicity nor death among the rats were observed for up to 14 days of the experimental period. The results of the subchronic toxicity study show that there were no significant changes observed in the hematology and organ histology. Some alterations to the relative organ weight and blood biochemistry were observed, but they were considered to be temporary effects and not an indication of toxic effects. The overall findings of this study indicate that the film formulation of κ-Carrageenan and konjac glucomannan is non-toxic up to a dose of 75 mg/kg bw, which could be considered a safe dose for soft capsule application.
Does Perception of Motor Competence Mediate Associations between Motor Competence and Physical Activity in Early Years Children?
Authors: Hall Charlotte J. S. , Eyre Emma L. J. , Oxford Samuel W. , Duncan Michael J.
Published: April 2019

Objectives: To examine if the relationship between physical activity (PA) and actual motor competence (MC) in British early years children is mediated by their perceived MC. Design: Cross-sectional convenience observational study. Methodology: MC was assessed with six locomotor skills (LC) and six object-control skills (OC) via the Test of Gross Motor Development-2. PA was measured via a wrist-worn triaxial accelerometer and PA grouped as daily total PA (TPA) and moderate-to-vigorous PA (MVPA). Perceived MC was assessed using the Pictorial Scale of Perceived Competence and Acceptance for Young Children. A total of 38 children (63% male; 37% female) aged between 3 and 6 years (5.41 ± 0.69) completed all assessments. Mediating impacts of perceived MC on the relationships between PA and MC were explored via backwards mediation regressions. Results: There were no mediating impacts of perceived MC on the relationship between PA and actual MC. Conclusions: The relationship between actual MC and PA is not mediated by perceived MC in a small sample of British early years childhood.
A Parametric Bayesian Approach in Density Ratio Estimation
Authors: Sadeghkhani Abdolnasser , Peng Yingwei , Lin Chunfang Devon
Published: April 2019

This paper is concerned with estimating the ratio of two distributions with different parameters and common supports. We consider a Bayesian approach based on the log–Huber loss function, which is resistant to outliers and useful for finding robust M-estimators. We propose two different types of Bayesian density ratio estimators and compare their performance in terms of frequentist risk function. Some applications, such as classification and divergence function estimation, are addressed.
The Impacts of Locational and Neighborhood Environmental Factors on the Spatial Clustering Pattern of Small Urban Houses: A Case of Urban Residential Housing in Seoul
Authors: Shin Myung-Cheul , Shin Gwang-Mun , Lee Jae-Su
Published: April 2019

Small housing has gained prominence in the housing market due to substantial shifts of both population and household structures in Korea. The study aims to examine the spatial clustering pattern of urban residential houses (URHs) in terms of the spatial statistics, and analyze the impacts of both locational and neighborhood residential factors on the formation of the spatial clustering pattern in the Seoul metropolitan area. It is found that the URHs represent a significant spatial clustering pattern based on the census tracts. The hotspots are mostly found in the outskirts of Seoul, where the development of small houses has been concentrated for ten years. Also, both locational and neighborhood residential factors have significant effects on the hotspot formation of the URH. The hotspots are more likely to be found in areas having many available sites for development, high demand for habitation, and high expected profits from developing small residences. Another significant factor is access to public transit, amenities, and employment centers. Therefore, it is necessary to design a rent subsidy program for potential residents and to encourage the development of housing in nearby hotspots with relatively lower land values. It is also important to establish policies and strategies for planning the housing supply and managing the residential environment in low-rise residential areas.
D. russelii Venom Mediates Vasodilatation of Resistance Like Arteries via Activation of Kv and KCa Channels
Authors: Kakumanu Rahini , Kuruppu Sanjaya , Rash Lachlan D. , Isbister Geoffrey K. , Hodgson Wayne C. , Kemp-Harper Barbara K.
Published: April 2019

Russell’s viper (Daboia russelii) venom causes a range of clinical effects in humans. Hypotension is an uncommon but severe complication of Russell’s viper envenoming. The mechanism(s) responsible for this effect are unclear. In this study, we examined the cardiovascular effects of Sri Lankan D. russelii venom in anaesthetised rats and in isolated mesenteric arteries. D. russelii venom (100 μg/kg, i.v.) caused a 45 ± 8% decrease in blood pressure within 10 min of administration in anaesthetised (100 μg/kg ketamine/xylazine 10:1 ratio, i.p.) rats. Venom (1 ng/mL–1 μg/mL) caused concentration-dependent relaxation (EC50 = 145.4 ± 63.6 ng/mL, Rmax = 92 ± 2%) in U46619 pre-contracted rat small mesenteric arteries mounted in a myograph. Vasorelaxant potency of venom was unchanged in the presence of the nitric oxide synthase inhibitor, L-NAME (100 µM), or removal of the endothelium. In the presence of high K+ (30 mM), the vasorelaxant response to venom was abolished. Similarly, blocking voltage-dependent (Kv: 4-aminopryidine; 1000 µM) and Ca2+-activated (KCa: tetraethylammonium (TEA; 1000 µM); SKCa: apamin (0.1 µM); IKCa: TRAM-34 (1 µM); BKCa; iberiotoxin (0.1 µM)) K+ channels markedly attenuated venom-induced relaxation. Responses were unchanged in the presence of the ATP-sensitive K+ channel blocker glibenclamide (10 µM), or H1 receptor antagonist, mepyramine (0.1 µM). Venom-induced vasorelaxtion was also markedly decreased in the presence of the transient receptor potential cation channel subfamily V member 4 (TRPV4) antagonist, RN-1734 (10 µM). In conclusion, D. russelii-venom-induced hypotension in rodents may be due to activation of Kv and KCa channels, leading to vasorelaxation predominantly via an endothelium-independent mechanism. Further investigation is required to identify the toxin(s) responsible for this effect.
The Gravitational Magnetoelectric Effect
Authors: Gibbons Gary , Werner Marcus
Published: April 2019

Electromagnetism in spacetime can be treated in terms of an analogue linear dielectric medium. In this paper, we discuss the gravitational analogue of the linear magnetoelectric effect, which can be found in multiferroic materials. While this is known to occur for metrics with non-zero mixed components, we show how it depends on the choice of spatial formalism for the electromagnetic fields, including differences in tensor weight, and also on the choice of coordinate chart. This is illustrated for Langevin–Minkowski, four charts of Schwarzschild spacetime, and two charts of pp gravitational waves.
LA INNOVACIÓN Y EL NUEVO PRODUCTO EN DESARROLLO
Authors: Jácome Lara Ibett , Albán Bautista Martha
Published: April 2019

La innovación actualmente cumple un papel fundamental para enfrentar la crisis económica en un mundo globalizado, donde se propende al desarrollo económico, creando un entorno  que favorezca la difusión de ideas para alcanzar el bienestar social mediante un crecimiento económico sostenido. La presente revisión de la literatura aportará al conocimiento en la identificación de los principales conceptos de innovación y su aplicación en el desarrollo de nuevos productos. En la actualidad la innovación se ha convertido en una prioridad de las políticas públicas, así como una necesidad imperiosa de las grandes, pequeñas y medianas empresas, tanto en el ámbito empresarial y en sectores como en la educación, salud, ecología y política, entre otros. Este tema constituye un elemento importante porque engloba procesos relacionados con el mercado, tecnologías de información y comunicación, actividades empresariales, redes y competencia, así como también habilidades, organizaciones, creatividad y transferencia de conocimientos. Su aplicación se puede dar en cualquier ámbito de la organización (finanzas, administración, ventas) en el caso de la presente investigación centraremos el estudio en la innovación en los productos o servicios debido a que la innovación permite el desarrollo de los mismos, manteniendo una competitividad en el mercado obteniendo resultados tanto económicos, sociales, tecnológicos y de prestigio.
Análisis de aspectos de normalización de la gestión editorial en la revista de ciencias humanísticas y sociales, ReHuSo.
Authors: Morales Intriago Juan Carlos , Pinargote Sornoza Daniel Alejandro
Published: April 2019

El presente estudio tiene por objetivo analizar los aspectos de normalización de la producción científica de la revista de ciencias humanísticas y sociales ReHuSo. La metodología tiene un diseño cuantitativo, cuya muestra está representada por el último volumen completo de la revista, vol.2 conformado por 3 números y una edición especial, correspondiente al año 2017. Para el proceso de evaluación se utilizó una adaptación del modelo de evaluación propuesta por Delgado, Ruiz, y Jiménez (2006) considerando las normas ISO 8, ISO 2015, CBE 1994, UKSG 1994, ANSI, ACS 1997, entre otras. Los resultados evidencian una media general de normalización del 92%, obtenida de aquellas secciones consideradas fundamentales en los mecanismos actuales de difusión científica.
La utilización de la radio como herramienta de aprendizaje: impacto de la materia radial desarrollo y habilidades del pensamiento en los estudiantes de nivelación de la UTM
Authors: Párraga Cano Maritza Guadalupe , Franco Segovia Ángela Monserrate , Navarrete Arteaga Jessica Paola
Published: April 2019

El perfil de la radio universitaria se define en gran parte a raíz de los contenidos de la programación, que constituye el espíritu de cada una de estas emisoras. La radio universitaria es opuesta a los contenidos de la radio comercial, porque tiene objetivos muy diferentes. Su propósito está relacionado con la educación, la cultura, la ciencia, la tecnología y el interés social. En este contexto, la Universidad Técnica de Manabí cuenta con una radio modalidad on line, que transmite una programación variada con contenidos académicos orientada a la comunidad universitaria. Por este medio los estudiantes de Nivelación cursan materias como Desarrollo y Habilidades del Pensamiento. En este texto se indaga en la forma en que por medio de la radia universitaria se fortalecen conocimientos propios de esta asignatura y los resultados que se obtienen con los estudiantes que empiezan sus estudios superiores.
Estudio CTS de un sistema de orientación vocacional profesional virtual para los jóvenes que aspiran ingresar en las carreras universitarias de la universidad técnica de Manabí, Ecuador
Authors: Santana Sardi Gustavo , Vigueras Moreno José , Velásquez Ávila René
Published: April 2019

La Orientación Vocacional Profesional en la gestión de ingreso a la Universidad incluye la implementación de nuevos sistemas que fortalezcan el trabajo del Centro de Promoción y Apoyo (CPAI) al Ingreso de la Universidad Técnica de Manabí (UTM).  La necesidad de reforzar el potencial y las bondades de este centro conduce al objetivo de este estudio: proponer un sistema virtual como alternativa hacia la Orientación Vocacional Profesional de los jóvenes que aspiran ingresar en las carreras universitarias en el Ecuador, a través de una investigación descriptiva aplicando métodos teóricos, empíricos y estadísticos, que dan como resultado, la posible obtención de nuevos espacios de aprendizaje, lo cual puede constituir un valor académico complementario satisfactorio.
La clase encuentro en la educación superior: algunas consideraciones teóricas -metodólogicas
Authors: Marín Llaver Leonardo Ramón , Suárez Meana José | Manuel , López González Yaikel , Pelegrín Naranjo Analien
Published: April 2019

El proceso de enseñanza – aprendizaje de la educación superior reclama de nuevas formas de organización del proceso pedagógico; por lo tanto se hace necesario el cambio en el rol protagónico del que enseña y del que aprende, lo cual trae consigo que la concepción de aprendizaje desarrollador y didáctica desarrolladora se efectué a través de diferentes formas organizativas y una de ellas es la clase encuentro. Es objetivo de este ensayo reflexionar sobre algunas cuestiones teóricas – metodológicas en torno a la clase encuentro como herramienta para lograr una mayor efectividad y eficacia en el aprendizaje de los estudiantes universitarios. En su elaboración, se emplearon métodos de investigación del nivel teórico que permitieron el procesamiento de la información, la caracterización del objeto de investigación, determinar sus fundamentos teóricos y metodológicos. Como conclusión se destaca la gran importancia que reviste la clase encuentro en la modalidad presencial y semipresencial en la educación superior, pues contribuye como ninguna otra a favorecer el autoaprendizaje, la autoevaluación, la independencia cognoscitiva  y el crecimiento personal en los estudiantes en la medida que se apropien de procedimientos y habilidades que le permitan acceder a los nuevos conocimientos.
Coordination chemistry and photoswitching of dinuclear macrocyclic cadmium-, nickel-, and zinc complexes containing azobenzene carboxylato co-ligands
Authors: Klose Jennifer , Severin Tobias , Hahn Peter , Jeremies Alexander , Bergmann Jens , Fuhrmann Daniel , Griebel Jan , Abel Bernd , Kersting Berthold
Published: April 2019

The synthesis of mixed-ligand complexes of the type [M2L(μ-L')]+, where L represents a 24-membered macrocyclic hexaaza-dithiophenolate ligand, L' is an azobenzene carboxylate co-ligand, and M = Cd(II), Ni(II) or Zn(II), is reported. A series of new complexes were synthesized, namely [M2L(μ-L')]+ (L' = azo-H, M = Cd (1), Ni (2); L' = azo-OH, M = Zn (3), Ni (4); L' = azo-NMe2, M = Zn (5), Cd (6), Ni (7); L' = azo-CO2Me, M = Cd (8), Ni (9)), and characterized by elemental analysis, electrospray ionization mass spectrometry (ESIMS), IR, UV–vis and NMR spectroscopy (for diamagnetic Zn and Cd complexes) and X-ray single crystal structure analysis. The crystal structures of 3' and 5–8 display an isostructural series of compounds with bridging azobenzene carboxylates in the trans form. The paramagnetic Ni complexes 2, 4 and 7 reveal a weak ferromagnetic exchange interaction with magnetic exchange coupling constant values between 21 and 23 cm−1 (H = −2JS1S2). Irradiation of 1 with λ = 365 nm reveals a photoisomerization of the co-ligand from the trans to the cis form.
Back to the Lithium Plateau with the [Fe/H] < −6 Star J0023+0307∗
Authors: Aguado David S. , González Hernández Jonay I. , Prieto Carlos Allende , Rebolo Rafael
Published: April 2019

We present an analysis of the Ultraviolet and Visual Echelle Spectrograph (UVES) high-resolution spectroscopic observations at the 8.2 m Very Large Telescope of J0023+0307, a main-sequence extremely iron-poor dwarf star. We are unable to detect iron lines in the spectrum but derive [Fe/H] < −6.1 from the Ca ii resonance lines assuming [Ca/Fe] ≥ 0.40. The chemical abundance pattern of J0023+0307, with very low [Fe/Mg] and [Ca/Mg] abundance ratios but relatively high absolute Mg and Si abundances, suggests J0023+0307 is a second generation star formed from a molecular cloud polluted by only one supernova in which the fallback mechanism played a role. We measure a carbon abundance of A(C) = 6.2 that places J0023+0307 on the low band in the A(C)–[Fe/H] diagram, suggesting no contamination from a binary companion. This star is also unique having a lithium abundance A(Li) = 2.02 ± 0.08, close to the level of the lithium plateau, in contrast with lower Li determinations or upper limits in all other extremely iron-poor stars. The upper envelope of the lithium abundances in unevolved stars spanning more than three orders of magnitude in metallicity (−6 < [Fe/H] < −2.5) defines a nearly constant value. We argue that it is unlikely that such uniformity is the result of depletion processes in stars from a significantly higher initial Li abundance, but suggests instead a lower primordial production, pointing to new physics such as decaying massive particles, varying fundamental constants, or nuclear resonances, that could have affected the primordial 7Li production.
Determining the Depth of Jupiter’s Great Red Spot with Juno: A Slepian Approach
Authors: Galanti Eli , Kaspi Yohai , Simons Frederik J. , Durante Daniele , Parisi Marzia , Bolton Scott J.
Published: April 2019

One of Jupiter’s most prominent atmospheric features, the Great Red Spot (GRS), has been observed for more than two centuries, yet little is known about its structure and dynamics below its observed cloud level. While its anticyclonic vortex appearance suggests it might be a shallow weather-layer feature, the very long time span for which it was observed implies it is likely deeply rooted, otherwise it would have been sheared apart by Jupiter’s turbulent atmosphere. Determining the GRS depth will shed light not only on the processes governing the GRS, but on the dynamics of Jupiter’s atmosphere as a whole. The Juno mission single flyby over the GRS (PJ7) discovered using microwave radiometer measurements that the GRS is at least a couple hundred kilometers deep. The next flybys over the GRS (PJ18 and PJ21), will allow high-precision gravity measurements that can be used to estimate how deep the GRS winds penetrate below the cloud level. Here we propose a novel method to determine the depth of the GRS based on the new gravity measurements and a Slepian function approach that enables an effective representation of the wind-induced spatially confined gravity signal, and an efficient determination of the GRS depth given the limited measurements. We show that with this method the gravity signal of the GRS should be detectable for wind depths deeper than 300 km, with reasonable uncertainties that depend on depth (e.g., ±100 km for a GRS depth of 1000 km).
Nonthermal Emission from the Interaction of Magnetized Exoplanets with the Wind of Their Host Star
Authors: Wang Xiawei , Loeb Abraham
Published: April 2019

We study the nonthermal emission from the interaction between magnetized Jupiter-like exoplanets and the wind from their host star. The supersonic motion of planets through the wind forms a bow shock that accelerates electrons that produce nonthermal radiation across a broad wavelength range. We discuss three wind mass-loss rates:

, 10−9,

corresponding to solar-type, T Tauri, and massive O/B-type stars, respectively. We find that the expected radio synchrotron emission from a Jupiter-like planet is detectable by the Jansky Very Large Array and the Square Kilometre Array at

out to a distance of ∼100 pc, whereas the infrared emission is detectable by the James Webb Space Telescope out to a similar distance. Inverse Compton scattering of the stellar radiation results in X-ray emission detectable by Chandra X-ray Observatory out to ∼150 pc. Finally, we apply our model to the upper limit constraints on V380 Tau, the first star–hot Jupiter system observed in radio wavelength. Our bow-shock model provides constraints on the magnetic field, the interplanetary medium, and the nonthermal emission efficiency in V380 Tau.
Globally distributed occurrences utilised in 200 spider species conservation profiles (Arachnida, Araneae)
Authors: Cardoso Pedro , Shirey Vaughn , Seppälä Sini , Henriques Sergio , Draney Michael , Foord Stefan , Gibbons Alastair , Gomez Luz , Kariko Sarah , Malumbres-Olarte Jagoba , Milne Marc , Vink Cor
Published: April 2019

Data on 200 species of spiders were collected to assess the global threat status of the group worldwide. To supplement existing digital occurrence records from GBIF, a dataset of new occurrence records was compiled for all species using published literature or online sources, from which geographic coordinates were extracted or interpreted from locality description data.

A total of 5,104 occurrence records were obtained, of which 2,378 were from literature or online sources other than GBIF. Of these, 2,308 had coordinate data. Reporting years ranged from 1834 to 2017. Most records were from North America and Europe, with Brazil, China, India and Australia also well represented.
Se raconter à soi-même et aux autres : atelier d’écriture avec des jeunes en foyer
Authors: Lefebvre Danielle
Published: April 2019

« Raconter constitue probablement le moyen le plus quotidien et le plus universel de mettre en forme son expérience vécue, la rendant par là même intelligible à soi-même et à autrui. Nous racontons pour partager la solitude, inhérente à notre condition humaine. » L’article résume une expérience d’atelier d’écriture avec des jeunes venus de pays lointains et maîtrisant mal la langue française. Et pourtant, ils vont écrire d’abord avec des listes de « j’aime, je n’aime pas » et puis de manière plus mûries ; certains vont pouvoir écrire ce qu’ils n’ont pas pu dire aux adultes qui n’ont pas été là où, eux, les attendaient. L’écriture redevient alors ce qu’elle a toujours été : un espace gratuit illustrant notre liberté personnelle.
Remarques pour une nouvelle édition du Liber de vita beati Vincentii écrit par Pierre Ranzano
Authors: Hodel Paul Bernard
Published: April 2019

[fr] En 1455, immédiatement après la canonisation de Vincent Ferrer, le dominicain sicilien Pietro Ranzano écrit le Liber de uita beati Vincentii, la première biographie du saint. Dans cet article les différentes éditions anciennes du Liber sont présentées et le contenu des manuscrits (des deux versions de l’oeuvre) est analysé afi n de rassembler les matériaux nécessaires pour une future nouvelle édition.
El poder y lo sagrado: intereses políticos y religiosos en la canonización de Vicente Ferrer
Authors: Ackerman Smoller Laura
Published: April 2019

El presente artículo examina algunas cuestiones políticas y religiosas relacionadas con la canonización de San Vicente Ferrer, a través de una atenta y a menudo compleja lectura de los materiales de la canonización, de cartas y de hagiografía contemporánea. Los más fervientes promotores de su canonización fueron los Montfort, Duques de Bretaña, donde el santo fue enterrado; ellos utilizaron su buena relación con el dominico para afirmar la sagrada legitimidad de su dinastía, que había llegado al poder después de una sangrienta guerra civil y que adoptó una imagen casi real, similar a la de la monarquía francesa. En su Aragón natal, la situación era más complicada. El dominico había aupado a los Trastámara al poder en 1412, pero su protagonismo en el anuncio de la sustracción de la Corona de Aragón a la obediencia del papa Benedicto XIII disminuyó su importancia simbólica en su propia tierra. Solo después de la conquista del Reino de Nápoles por Alfonso V empezaron los Trastámara a impulsar con fervor la apertura del proceso de canonización, como parte de una estrategia para mostrar el favor divino con el que contaba el nuevo “régimen” aragonés en Nápoles. Los promotores de la canonización de Ferrer sabían que se encontrarían con varios impedimentos –presumiblemente, los rumores sobre sus convicciones heréticas, como aquellas vinculadas a la predicación de Vicente Ferrer sobre el Anticristo, y su posición respecto al Cisma y al Concilio de Constanza. En contrapartida, los defensores del nuevo santo lo presentaron sutilmente como sabio predicador que, gracias a sus sermones apocalípticos, movía a la multitud a la penitencia y que no reparaba en esfuerzos para conseguir la unidad de la iglesia dividida.
Analysis and Mathematical Modeling of Car-Following Behavior of Automated Vehicles for Safety Evaluation
Authors: Rao Sughosh J. , Seitz Timothy , Lanka Venkata Raghava Ravi , Forkenbrock Garrick
Published: April 2019

With the emergence of Driving Automation Systems (SAE levels 1-5), the necessity arises for methods of evaluating these systems. However, these systems are much more challenging to evaluate than traditional safety features (SAE level 0). This is because an understanding of the Driving Automation system’s response in all possible scenarios is desired, but prohibitive to comprehensively test. Hence, this paper attempts to evaluate one such system, by modeling its behavior. The model generated parameters not only allow for objective comparison between vehicles, but also provide a more complete understanding of the system. The model can also be used to extrapolate results by simulating other scenarios without the need for conducting more tests.

In this paper, low speed automated driving (also known as Traffic Jam Assist (TJA)) is studied. This study focused on the longitudinal behavior of automated vehicles while following a lead vehicle (LV) in traffic jam scenarios. The automated vehicle behavior is modeled using three car-following models. The models are then used to predict the behavior of the vehicle in a randomized scenario. This also serves as validation of the models.

In this study, three vehicles were used: a 2017 Mercedes E300, a 2017 Tesla Model S 90D, and a 2017 Volvo S90. The vehicles were tested using a typical traffic scenario, where the subject vehicle (SV) follows an LV (a 2015 Lexus LS460L). Two different velocity profiles were used, one for model fit and another for model validation. The acceleration, velocity, and position of both the SV and LV were recorded. The data for each SV were fit to three car-following models: Gazis-Herman-Rothery (GHR) model, and two novel physics-based car-following models; Stationary Time-To-Collision (STTC) model and Spring-Mass-Damper (SMD) model.

The performance of these models was evaluated by assessing their ability to predict the resulting acceleration of the SV when presented with random LV speed data. The car-following model parameters for the vehicles were then used to objectively compare their relative performance and safety. The model parameters were used to compute metrics like the SV’s response delay, system dynamics, steady-state response, time-to-collision (TTC) characteristics, etc.

The results indicate that the new SMD and STTC models are comparable in performance to the GHR model in predicting the SV accelerations. The SMD model, in addition to being accurate, also gives further insight into the safety of the vehicles. Though the STTC model predicted the SV acceleration accurately, the model coefficients could not be used to reliably gain insights into the vehicle following behavior.
High Load Expansion of Catalytic EGR-Loop Reforming under Stoichiometric Conditions for Increased Efficiency in Spark Ignition Engines
Authors: Szybist James P. , Pihl Josh , Huff Shean , Kaul Brian
Published: April 2019

The use of fuel reformate from catalytic processes is known to have beneficial effects on the spark-ignited (SI) combustion process through enhanced dilution tolerance and decreased combustion duration, but in many cases reformate generation can incur a significant fuel penalty. In a previous investigation, the researchers showed that, by controlling the boundary conditions of the reforming catalyst, it was possible to minimize the thermodynamic expense of the reforming process, and in some cases, realize thermochemical recuperation (TCR), a form of waste heat recovery where exhaust heat is converted to usable chemical energy. The previous work, however, focused on a relatively light-load engine operating condition of 2000 rpm, 4 bar brake mean effective pressure (BMEP). The present investigation demonstrates that this operating strategy is applicable to higher engine loads, including boosted operation up to 10 bar BMEP. By controlling the reforming catalyst boundary conditions, it is possible to achieve fuel reforming without experiencing high temperature exotherms that could be damaging to the catalyst. Additionally, the thermodynamic air handling consequences of operating a highly dilute strategy at high loads is quantified. The results confirm that this operating strategy provides an efficiency benefit at all conditions investigated, with relative efficiency increases of 3-6%, and is therefore applicable over wider regions of the engine operating map.
Key Fuel Injection System Features for Efficiency Improvement in Future Diesel Passenger Cars
Authors: Beatrice Carlo , Di Blasio Gabriele , Pesce Francesco Concetto , Vassallo Alberto , Avolio Giovanni , Ianniello Roberto
Published: April 2019

Diesel will continue to be an indispensable energy carrier for the car fleet CO2 emission targets in the short-term. This is particularly relevant for heavy-duty vehicles as for mid-size cars and SUVs. Looking at the latest technology achievements on the after-treatment systems, it can be stated that the concerning about the NOx emission gap between homologation test and real road use is basically solved, while the future challenge for diesel survival is to keep its competitiveness in the CO2 vs cost equation in comparison to other propulsion systems.

The development of the combustion system design still represents an important leverage for further efficiency and emissions improvements while keeping the current excellent performance in terms of power density and low-end torque.

The paper describes the results achieved in developing a new diesel combustion system for car application that, leveraging on the high flexibility of the latest fuel injection technology, combines outstanding power and fuel efficiency with low pollutant emissions in ultralight engine designed for lower maximum peak cylinder pressure. The study has been carried out on a 0.5l single-cylinder engine on which an advanced and last generation common rail system, capable of very high injection pressure, has been installed.

Through an extensive DoE-based test campaign in which all engine operating parameters have been carefully parametrized, the capability to achieve high power density and excellent fuel economy with low engine-out pollutant emissions has been demonstrated and discussed in the paper.
Fine Tuning the SST k − ω Turbulence Model Closure Coefficients for Improved NASCAR Cup Racecar Aerodynamic Predictions
Authors: Fu Chen , Bounds Charles , Uddin Mesbah , Selent Christian
Published: April 2019

Faster turn-around times and cost-effectiveness make the Reynolds Averaged Navier-Stokes (RANS) simulation approach still a widely utilized tool in racecar aerodynamic development, an industry where a large volume of simulations and short development cycles are constantly demanded. However, a well-known flaw of the RANS methodology is its inability to properly characterize the separated and wake flow associated with complex automotive geometries using the existing turbulence models. Experience suggests that this limitation cannot be overcome by simply refining the meshing schemes alone. Some earlier researches have shown that the closure coefficients involved in the RANS turbulence modeling transport equations most times influence the simulation prediction results. The current study explores the possibility of improving the performance of the SST k − ω turbulence model, one of the most popular turbulence models in motorsports aerodynamic applications, by re-evaluating the values of certain model closure constants. A detailed full-scale current generation NASCAR Cup racecar was used for the investigation. The simulations were run using a commercial CFD package STAR-CCM+ (version 13.04.010). Five different closure coefficients in the SST k − ω model, σk1, σk2, σω1, σω2 and β∗, were examined. The investigation suggests the influence of each closure coefficient on the simulation prediction results are significantly different. β∗ appeared to be the most sensitive closure coefficient whereas both σk1 and σk2 had almost no effect on the NASCAR Cup racecar aerodynamic predictions. This study proposes a new set of SST k − ω turbulence model closure coefficients which has the potential of providing better-correlated aerodynamic predictions of a NASCAR Cup racecar under a range of different operating conditions.
Increasing the Aerodynamic Performance of a Formula Student Race Car by Means of Active Flow Control
Authors: Steinfurth Ben , Berthold Arne , Feldhus Steffen , Haucke Frank , Weiss Julien
Published: April 2019

This article involves an experimental study regarding the capability of fluidic actuators to increase the aerodynamic performance of a four-element race car rear wing. Sweeping jet actuators are integrated in the upper flap, of which the angle of attack is increased by up to ΔαF3 = 40° with reference to a passively optimized setup. Different velocities of the emitted sweeping jets are applied to study the influence of momentum coefficients cμ = 0.04 … 0.98%. To prove the feasibility of the approach, flow control is first applied to a stand-alone rear wing tested in a small wind tunnel. Subsequently, a realistic race car model featuring the controlled rear wing is investigated in a larger-scale wind tunnel. Employing particle image velocimetry, flow visualization techniques as well as pressure and force measurements, we show that the velocity field on the suction side of the upper flap is characterized by flow separation of different degrees when the angle of attack is increased beyond ΔαF3 = 20° (rear wing only) and ΔαF3 = 30° (complete race car). Generally, the employed fluidic devices have a positive impact in terms of the aerodynamic performance for all investigated angles of attack as overall downforce increases by up to 22 % are achieved, however accompanied by larger drag. Nonetheless, an in-house simulation indicates a potential lap time reduction of 0.17 % at the Formula Student endurance race circuit at Hockenheim under permanent actuation. Even greater gains are to be expected for a selective employment during cornering only or for skidpad and acceleration competitions.
Aerodynamic Sensitivity Analysis of Wheel Shape Factors
Authors: Hirose Kenichi , Kawamata Hideyuki , Oshima Munehiko
Published: April 2019

Wheels play an important role in determining the aerodynamic drag of passenger vehicles. This is because the contribution of wheels to aerodynamic drag comes from not only the wheels themselves, but also from the interference effect between wheel wakes and the base wake. As far as the authors are aware, there have been no reports about aerodynamic drag sensitivity to wheel shape factors for different vehicle types and different exterior body shapes. The purpose of this study was to clarify CD sensitivity to wheel shape factors for a sedan and an SUV, including different rear fender shapes. Many different wheel configurations were investigated in terms of the CD, base pressure and flow fields in wind tunnel tests. Multiple regression analyses were conducted to clarify CD sensitivity to each wheel shape factor based on the test data. This study revealed high CD sensitivity factors for both the sedan and SUV. The findings show that wheel shape factors and related CD sensitivities provide design guidelines for reducing aerodynamic drag.
Research on Multi-Vehicle Coordinated Lane Change of Connected and Automated Vehicles on the Highway
Authors: Liu Di , Wu Jian , Ye Yifan , Shi Jiangchao , Wang Yuan
Published: April 2019

With the rapid development of modern economy and society, traffic congestion has become an increasingly serious problem. Vehicle cooperative driving can alleviate traffic congestion and improve road traffic capacity. Compare with vehicle separate control, cooperative driving combines various vehicle systems, and highly integrates information on obstacle location, vehicle status and driving intention. Then the controller uniformly issues instructions to ensure the orderly driving of the platoon. In the cooperative driving platoon, the displacement difference and the speed difference between vehicles have a certain relationship, which reduces the possibility of traffic accidents and then improves the safety of driving. In the process of cooperative driving, if there are multiple vehicles whose speeds don’t meet the current lane requirements, or if there are obstacles ahead, multi-vehicle lane change measures must be taken. This paper establishes a vehicle system based on "human-vehicle-environment-task" generalized mechanical dynamics system and multi-objective coordinated control, which solves the problem of long distance and low efficiency in the process of lane change. The strategy proposed can also slow down the lateral and longitudinal impact of passengers and reduce the fuel consumption. In view of the above problems, the article firstly constructs a kinematic model that characterizes the behavior mechanism of intelligent vehicles. Next, the lateral and longitudinal coordinated control method is proposed, and trajectory tracking is realized based on MPC algorithm. Finally, the control performance is verified by PreScan software, and the stability and robustness of the collaborative control system are analyzed. This paper solves the problem of multi-objective collaborative control that comprehensively considers intelligent driving safety, passenger comfort and lane change efficiency. The results have important research significance for improving the safety, comfort, energy saving and environmental protection performance of intelligent vehicles and traffic environments.
Optimisation of Image Processing Parameters for Flame Image Velocimetry (FIV) Measurement in a Single-Cylinder, Small-Bore Optical Diesel Engine
Authors: Rao Lingzhe , Kook Sanghoon
Published: April 2019

High-speed soot luminosity movies are widely used to visualise flame development in optical diesel engines thanks to its simple setup and relatively low cost. Recent studies demonstrated the high-speed soot luminosity movies are not only effective in showing the overall distribution and temporal evolution of sooting flames but also flow fields within the flame through the application of combustion (or flame) image velocimetry. The present study aims to improve this imaging technique by systematically evaluating key image processing parameters based on high-speed soot luminosity movies obtained from a single-cylinder, small-bore optical diesel engine. The raw soot luminosity movies are processed using PIVlab - a Matlab-based open-source code widely used for particle image velocimetry (PIV) applications. The images are pre-processed using the Contrast-Limited Adaptive Histogram Equalization (CLAHE) filter before the velocity vectors are determined through the multi-pass Discrete Fourier Transform (DFT) approach. This is then post processed to find the optimised filter size, interrogation window size, step size and velocity limit for minimal interpolation counts. As a result, a four-step DFT approach with interrogation windows set at 32-32-16-16 pixels, CLAHE filter size at 16 pixels and velocity limit at 3 pixels/frame is determined as optimised. The derived flow fields show that the internal flame pattern change, as demonstrated by previous studies, can be used to obtain the flow vectors within the flame successfully. From a selected example movie, the processed images show the evolution of multiple vortex structures as a result of strong jet-wall and jet-to-jet interactions as well as the swirl effects.
Ensuring Fuel Economy Performance of Commercial Vehicle Fleets Using Blockchain Technology
Authors: Anwar Hamza , Arasu Mukilan , Ahmed Qadeer
Published: April 2019

In the past, research on blockchain technology has addressed security and privacy concerns within intelligent transportation systems for critical V2I and V2V communications that form the backbone of Internet of Vehicles. Within trucking industry, a recent trend has been observed towards the use of blockchain technology for operations. Industry stakeholders are particularly looking forward to refining status quo contract management and vehicle maintenance processes through blockchains. However, the use of blockchain technology for enhancing vehicle performance in fleets, especially while considering the fact that modern-day intelligent vehicles are prone to cyber security threats, is an area that has attracted less attention. In this paper, we demonstrate a case study that makes use of blockchains to securely optimize the fuel economy of fleets that do package pickup and delivery (P&D) in urban areas. We implement a consortium blockchain infrastructure, as opposed to a fully public blockchain (similar to the blockchain underlying Bitcoin) which is arguably not real-time or well suited for this safety-critical application. By leveraging in real-time a fleet vehicle’s powertrain status, geospatial traffic data, along with driver information, the fleet vehicle acts as a node ready for data transactions in the blockchain network. Each such vehicle in the fleet communicates with its local central hub, and these secure exchanges of data and information act as immutable blockchain transactions. Consensus within the fleet is established when multiple vehicles report data updates for a given subregion in the fleet route map. The proposed infrastructure will support a fleet route planning algorithm running on the local hub, responsible for optimizing fuel economy for the fleet, increasing its reliability and credibility.
Finite Element Analyses of Structural Stresses near Dissimilar Spot Joints in Lap-Shear Specimens
Authors: Sung Shin-Jang , Pan Jwo
Published: April 2019

Structural stress distributions near nearly rigid, dissimilar and similar spot joints in lap-shear specimens are investigated by 3-D finite element analyses. A set of accurate closed-form structural stress solutions is first presented. The closed-form structural stress solutions were derived for a rigid inclusion in a square thin plate under various loading conditions with the weak boundary conditions along outer edges or semi-circular paths by satisfying the equilibrium conditions. Finite element analyses with different joint material behaviors, element types and mesh designs are conducted to examine the structural stress solutions near the spot joints in lap-shear specimens. The results of the finite element analyses indicate that the computational structural stress solutions on the edge of the joint depend on the joint material behavior, element type, and mesh design. However, the solutions do not significantly depend on the joint material behavior, element type, and mesh design at the radius distance of one and a half joint radius away from the joint where fatigue failures of mechanical joints, such as flow drill screw and self-piercing rivet joints, may occur.
A Systems Approach in Developing an Ultralightweight Outside Mounted Rearview Mirror Using Discontinuous Fiber Reinforced Thermoplastics
Authors: Ramesh Senthil Raj , Yerra Veera Aditya , Pradeep Sai Aditya , Pilla Srikanth
Published: April 2019

Fuel efficiency improvement in automobiles has been a topic of great interest over the past few years, especially with the introduction of the new CAFE 2025 standards. Although there are multiple ways of improving the fuel efficiency of an automobile, lightweighting is one of the most common approaches taken by many automotive manufacturers. Lightweighting is even more significant in electric vehicles as it directly affects the range of the vehicle. Amidst this context of lightweighting, the use of composite materials as alternatives to metals has been proven in the past to help achieve substantial weight reduction. The focus of using composites for weight reduction has however been typically limited to major structural components, such as BiW and closures, due to high material costs. Secondary structural components which contribute approximately 30% of the vehicle weight are usually neglected by these weight reduction studies. This work is an attempt to prove that composites can also be used effectively in the weight reduction of secondary structural components, while meeting the desired standards on mechanical performance, cost, and scalability. Discontinuous fiber-reinforced injection-molded materials offer excellent mechanical properties and very high lightweighting potential. In this paper, a secondary structural component such as outside mounted rearview mirror assembly is used to study the effect of performance and cost while trying to achieve a mass reduction of at least 30%. An injection-molded long carbon fiber-reinforced nylon is used to replace the aluminum structure in the baseline mirror assembly. In addition to material replacement, 20%-parts consolidation was achieved due to the design freedom offered by these materials. A virtual plant layout was developed to determine the cost of series manufacturing. In conclusion, this paper provides a strong case for the use of these material systems to lightweight small and secondary structural components.
Reliability Physics Approach for High-Density Ball Grid Arrays in Autonomous Vehicle Applications
Authors: Serebreni Maxim , Sharon Gil , Blattau Nathan , Hillman Craig
Published: April 2019

Integration of advanced sensing systems in autonomous vehicles is possible due to high performance processors that utilize high-density ball grid array (HD-BGA) packaging. The configuration of advanced sensors within autonomous vehicles requires the placement of processing modules within non-conventional vehicles compartments that can drastically influence the reliability of HD-BGAs. Durability of HD-BGAs to different loads depend on their location within the vehicle as well as the form factor of the package itself. Reliability Physics Approach (RPA) combines simulation tools and empirical models to predict the reliability of advanced electronic packages under complex environmental and operational loads by identifying the susceptibility of electronic components to the dominant failure mechanism. In this paper, the reliability of an electronic module will be investigated under various vibration loads at different vehicle compartments and the influence of mounting configuration of electronic module to housing under thermal loads. In addition, the BGA form factor will be investigated to demonstrate the implementation of RPA early in the design process to develop such mitigation techniques as underfill selection to improve the reliability of HD-BGAs in autonomous vehicle applications.